The present invention relates to semi-conductor assemblies, a method of manufacturing them, and bonding agents useful therefor. More particularly the present invention pertains to light emitting diode assemblies, methods of manufacturing them and bonding agents useful therefor.
In present light emitting diode (hereinafter "LED") assemblies, the N-side of the finished LED chip or die is bonded to a substrate (commonly called a "holder", "header" or "frame") using various metallurgical alloys or conductive epoxies to bond the N-side to the electrode of the substrate. The P-side of the LED chip, where the light is generated, is connected to a cover electrode by various wire bonding techniques, such as thermo-compression and ultrasonic bonding, in such a manner as to minimize obstruction of the P-side and thus permit observation of the emitted light.
The wire bonding of the P-side of the LED chip to the cover electrode is an expensive, low reliability and low yield process. For example, for an eight-digit display there are 64 light emitting segments (7 segments for the numeric portion of each digit and 1 segment for the decimal point portion of each digit) to be wire bonded. The total number of wire-bonding operations required to produce such an eight-digit display is 128, since each wire bond must be connected to the diode and to the cover electrode. The requirement for such a vast number of wire-bonding operations not only increases the cost of manufacturing the display, but also poses reliability problems.
Accordingly, it is an object of the present invention to provide a novel semiconductor assembly devoid of wire bonding.
It is another object to provide such a semiconductor assembly of improved reliability.
It is also an object to provide such a semiconductor assembly for light emitting diodes, the assembly providing improved light output efficiency.
Another object of the present invention is to provide a novel method of manufacturing such semiconductor assemblies which affords economies of manufacture, improved reliability and in the case of light emitting diode assemblies, improved light output efficiency.
A further object is to provide novel bonding agents and techniques for using the same.